The invention relates in general to the field of encryption and decryption. In particular, it is directed to encryption/decryption methods using initialization vectors or values that are generated for every storage block.
The General Parallel File System (GPFS) will include native encryption support starting from GPFS 4.1. One of the supported encryption modes is CBC-IV. When encrypting a file using the CBC-IV mode, unique initialization values (IVs) are generated for every “storage block” that is encrypted (512 bytes in the case of GPFS, though this size can vary) to ensure randomized encryption. Because storing this IV would be prohibitively expensive on a filesystem (there is no extra space in a disk sector), the IVs have to be generated on the fly. Many, if not all related encrypting file systems adopt that same approach, see for instance M Halcrow, eCryptfs: an enterprise class encrypting file system.